I am also surprised by the lack of replies but there are a couple of threads about this, so maybe everyone has given their opinion?
I spent 3 winters in SP and then 3 in Aiken and now have moved permanently to Aiken. I found SP to be a lovely town, but it did get cold, frozen ground a couple of days, and there was a lack of close schooling shows during the winter. Things wake up in March, but there were a couple of days I couldn’t ride because of the weather. Not New England bad, just worth mentioning. 5-10 degrees different between the places makes a difference when you are straddling freezing.
In Aiken, there has never been a day I couldn’t ride. No frozen ground. Some cold, wet days, but never dangerous. There’s also a schooling opportunity running every day of the week except Mondays it seems, from dressage, H/J, eventing, foxhunting. My barn does eventing, H/J, and foxhunting so having that variety was key. There’s just more stuff going on in Aiken. In SP, there’s a great foxhunt. In Aiken, there’s 4 within an hour and 7 within 1.5. In SP, there’s a nice dressage schooling series but no H/J shows over the winter. In Aiken, there’s schooling H/J shows nearly every weekend. Etc.
I work from home so my advice would be to join one of the many Aiken Equestrian groups on FB and put an ISO ad for housing. Same for SP. Be very specific, especially about wifi, because internet is not a given in Aiken, especially if you are out in the more horsey areas. My first rentals had no, zero, nada internet and I had to buy a cellular router.
For hubby:
SP has better restaurants because of the golfers, and a movie theatre, maybe night life?
Aiken has a few good restaurants, a terrible movie theatre and little night life. However, Columbia is actually a very fun, surprising town and it’s an hour away if you are on the west side of town. A lot of the social life in Aiken revolves around the many horse activities, so lots of tailgating at polo or steeplechase which is good fun and might be enough for non-horsey spouses. There’s also live music downtown every Thursday and lots of street festivals.
Good luck!